net: dsa: microchip: Implement recommended reset timing

The datasheet for the ksz9893 and ksz9477 switches recommend waiting at
least 100us after the de-assertion of reset before trying to program the
device through any interface.

Also switch the existing msleep() call to usleep_range() as recommended
in Documentation/timers/timers-howto.rst. The 2ms range used here is
somewhat arbitrary, as long as the reset is asserted for at least 10ms
we should be ok.

Signed-off-by: Paul Barker <pbarker@konsulko.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index 8d53b12..a317386 100644 (file)
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/drivers/net/dsa/microchip/ksz_common.c
@@ -400,8 +400,9 @@ int ksz_switch_register(struct ksz_device *dev,
 
        if (dev->reset_gpio) {
                gpiod_set_value_cansleep(dev->reset_gpio, 1);
-               mdelay(10);
+               usleep_range(10000, 12000);
                gpiod_set_value_cansleep(dev->reset_gpio, 0);
+               usleep_range(100, 1000);
        }
 
        mutex_init(&dev->dev_mutex);